1,622 research outputs found

    Assessment of carotenoid production by Dunaliella salina in different culture systems and operation regimes

    Get PDF
    The effect of operation regime and culture system on carotenoid productivity by the halotolerant alga Dunaliella salina has been analyzed. Operation strategies tested included batch and semi continuous regime, as well as a two-stage approach run simultaneously in both, open tanks and closed reactor. The best results were obtained with the closed tubular photobioreactor. The highest carotenoid production (328.8 mg carotenoid l−1 culture per month) was achieved with this culture system operated following the two-stage strategy. Also, closed tubular photobioreactor provided the highest carotenoid contents (10% of dry weight) in Dunaliella biomass and β-carotene abundance (90% of total carotenoids) as well as the highest 9-cis to all-trans β-carotene isomer ratio (1.5 at sunrise).Comisión Interministerial de Ciencia y Tecnología IFD 1997-1780IFAPA CO3-125Plan Andaluz de Investigación CVI13

    Étale Covers and Fundamental Groups of Schematic Finite Spaces

    Get PDF
    [EN] We introduce the category of finite étale covers of an arbitraryschematic space X and show that, equipped with an appropriate naturalfiber functor, it is a Galois Category. This allows us to define the étale fundamental group of schematic spaces. If X is a finite model of a schemeS, we show that the resulting Galois theory on X coincides with theclassical theory of finite étale covers on S, and therefore, we recover the classical étale fundamental group introduced by Grothendieck. Toprove these results, it is crucial to find a suitable geometric notion ofconnectedness for schematic spaces and also to study their geometric points. We achieve these goals by means of the strong cohomologicalconstraints enjoyed by schematic spaces.Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCLE

    Assessment of a Universal Reconfiguration-less Control Approach in Open-Phase Fault Operation for Multiphase Drives

    Get PDF
    Multiphase drives have been important in particular industry applications where reliability is a desired goal. The main reason for this is their inherent fault tolerance. Di erent nonlinear controllers that do not include modulation stages, like direct torque control (DTC) or model-based predictive control (MPC), have been used in recent times to govern these complex systems, including mandatory control reconfiguration to guarantee the fault tolerance characteristic. A new reconfiguration-less approach based on virtual voltage vectors (VVs) was recently proposed for MPC, providing a natural healthy and faulty closed-loop regulation of a particular asymmetrical six-phase drive. This work validates the interest in the reconfiguration-less approach for direct controllers and multiphase drives

    The central parsecs of M87: jet emission and an elusive accretion disc

    Full text link
    We present the first simultaneous spectral energy distribution (SED) of M87 core at a scale of 0.4 arcsec (32pc\sim 32\, \rm{pc}) across the electromagnetic spectrum. Two separate, quiescent, and active states are sampled that are characterized by a similar featureless SED of power-law form, and that are thus remarkably different from that of a canonical active galactic nuclei (AGN) or a radiatively inefficient accretion source. We show that the emission from a jet gives an excellent representation of the core of M87 core covering ten orders of magnitude in frequency for both the active and the quiescent phases. The inferred total jet power is, however, one to two orders of magnitude lower than the jet mechanical power reported in the literature. The maximum luminosity of a thin accretion disc allowed by the data yields an accretion rate of <6×105Myr1< 6 \times 10^{-5}\, \rm{M_\odot \, yr^{-1}}, assuming 10% efficiency. This power suffices to explain M87 radiative luminosity at the jet-frame, it is however two to three order of magnitude below that required to account for the jet's kinetic power. The simplest explanation is variability, which requires the core power of M87 to have been two to three orders of magnitude higher in the last 200 yr. Alternatively, an extra source of power may derive from black hole spin. Based on the strict upper limit on the accretion rate, such spin power extraction requires an efficiency an order of magnitude higher than predicted from magnetohydrodynamic simulations, currently in the few hundred per cent range.Comment: 18 pages, 6 figures. Accepted for publication in MNRA

    Relationships among main soil properties and three N availability indices.

    Get PDF
    A biological (aerobic incubation for 3 and 6 weeks) and a chemical method [successive extractions with cold 0.1 (H1-N) and 0.5 M HCl (H2-N)] were applied to 21 soils to determine: a) the potentially mineralizable-N; b) the most useful soil variables for predicting soil N availability; and c) their usefulness for predicting N uptake by a greenhouse wheat crop. At t=3, both net N mineralized (NNM) and net N mineralization rate (NNMR) were correlated: a) positively with SOM- and CEC-related variables; and b) positively with soil δ 15N and negatively with soil pH, suggesting that Nmineralization, dominated by nitrification, is associated with NO3 --N losses and soil acidification. At t=6, all previously discussed variables were important for NNM, but not for NNMR, mainly controlled by the available-P content. The importance of H1-N increased with N2-inputs and decreased with NO3 - losses and soil-N. Relationships of H1-N and H2-N with soil CEC and texture showed the strong relations among nutrients content, biological activity and N mineralization, as well as the recalcitrance of clay-bounded SOM. Soil total-N correlations with wheat-N in absolute amount (positive) and as percentage of soil-N (negative) showed an important supply of available-N by N-rich soils, despite their slow N turnover. The best regression models for wheat-N always included 1-2 main available nutrients. The percentage of soil N exported to plant biomass was negatively correlated with noncrystalline Al compounds and soil δ 15N. Mineralized-N and wheat-N pools did not share many correlations with soil properties and seemed to come from different sources; consequently, the former pool, which only explained a quarter of wheat-N variance, was not more useful than soil total-N for predicting it. Only a positive correlation with soil total-N was shared by wheat-N and hydrolysable-N, highlighting that the latter N pools are mainly unrelated. Nevertheless, half of wheat-N variation was explained by its negative relationship with the percentage of soil-N as (H1+H2)-N; a possible explanation is that chemically labile N is also biologically labile, being cumulated because of a limiting factor for microbial N mineralization or plant growth and emerging as a good predictor for wheat-N uptake.Peer reviewe

    IBSE: An OWL Interoperability Evaluation Infrastructure

    Get PDF
    The technology that supports the Semantic Web presents a great diversity and, whereas all the tools use different types of ontologies, not all of them share a common knowledge representation model, which may pose problems when they try to interoperate. The Knowledge Web European Network of Excellence is organizing a benchmarking of interoperability of ontology tools using OWL as interchange language with the goal of assessing and improving tool interoperability. This paper presents the development of IBSE, an evaluation infrastructure that allows executing automatically the benchmarking experiments and provides an easy way of analysing the results. Thus,including new tools into the evaluation infrastructure will be simple and straightforward

    Reliability analysis for systems with large hydro resources in a deregulated electric power market

    Get PDF
    This work describes a procedure that determines the optimal allocation for the yearly energy resulting from random water inflows to the different subperiods of a year so that the expected benefits are maximized. Its main idea is to distribute the energy stored in reservoirs in each period into two parts: one is directly sold in the energy market, while the other is made available to cover any unplanned outages of thermal units. The method proposed fulfills two objectives, to distribute the hydro energy optimally according to economic criteria and to assess the impact of new market rules on the reliability of an electric system. The procedure will be illustrated by an example based on the Spanish generating system.This work was supported by the Project PB-98-0728 of the Ministerio de Educación, Cultura y Deporte, Spain.Publicad

    La fisión mediada por DRP1 tiene un papel importante en las enfermedades de Alzheimer y Parkinson

    Get PDF
    Our objectives were to perform a bibliometric analysis with which to highlight the role of Drp1 in the pathogenesis of AD and PD as a fundamental regulator of mitochondrial fusion and fission homeostasis, in addition to highlighting Drp1 as a possible therapeutic target in AD and PD.Nuestros objetivos son realizar un análisis bibliométrico con el que destacar la relevancia de Drp1 en la patogénesis de la EA y la EP como regulador fundamental de la homeostasis de la fusión y fisión mitocondrial, además de destacar a Drp1 como posible diana terapéutica en la EA y la EP.Ciencias Experimentale
    corecore